Does javascript export references or deep copies of objects?

Question

const obj = {A: 2}
module.exports = obj

If another module imports from the above module, will it get a deep copy of obj or just a reference?

also [Does module.require(...).* return a copy of module.exports.* or a reference of it?](https://stackoverflow.com/questions/13346046/does-module-require-return-a-copy-of-module-exports-or-a-reference-of-i) — pilchard, Nov 24 '22 at 21:06

score 2 · Accepted Answer · answered Nov 24 '22 at 21:01

2

Exports work exactly the same way as every other way of passing values around.

The value of obj is a reference to the object.

A copy of that value (still a reference) is assigned to exports.

Anything requireing that module will get a copy of that value (still a reference).

answered Nov 24 '22 at 21:01

Quentin

isn't that dangerous? What if an importer modifies the object? Then that will modify it for every other importer? How to export a deep copy? – Bear Bile Farming is Torture Nov 24 '22 at 21:04
"Then that will modify it for every other importer?" — Yes. This can be useful. – Quentin Nov 24 '22 at 21:05
2

"How to export a deep copy?" — Export a factory function instead of a plain object. – Quentin Nov 24 '22 at 21:05

score 1 · Answer 2 · answered Nov 24 '22 at 21:04

I would say references because modules have their own execution context. meaning they track state of the context as you import / re import it.

2 Answers2